U.S. patent number 4,786,202 [Application Number 06/700,857] was granted by the patent office on 1988-11-22 for dual load path pin clevis joint.
This patent grant is currently assigned to The United States of America as represented by the Secretary of the Air. Invention is credited to Alison M. Arnold, Ronald G. Reed.
United States Patent |
4,786,202 |
Arnold , et al. |
November 22, 1988 |
**Please see images for:
( Certificate of Correction ) ** |
Dual load path pin clevis joint
Abstract
A novel dual load path connector for pivotally joining a movable
member to a structural member, is described which comprises a pair
of spaced apart lugs attached to a first of the members, each of
the lugs including an outwardly projecting boss, a clevis disposed
between the lugs and attached to the first member, a pivot pin,
received by the lugs and clevis, which may support a self-aligning
bearing between the ends of the clevis, and a connecting link
assembly including a first connecting link pivotally supported at a
first end on the pin and connected at the other end to the second
member, and a pair of second connecting links pivotally supported
at respective first ends on the bosses and at the second ends to
the second member, the first connecting link, pin and clevis
providing a first load bearing path between the structural and
movable members, and the second connecting links, bosses and lugs
providing a second load bearing path. Alternatively, a pair of
spaced apart fail safe lugs attached to the first member and a pair
of flanged bushings received by the lugs may be utilized to provide
a first load bearing path along the first connecting link, pin and
lugs and a second load bearing path along the second connecting
links, flanged bushings, and lugs. In a further embodiment, two
pairs of spaced apart lugs are attached to the first member and a
pair of flanged bushings are received by the respective lug pairs
to provide a first load bearing path along the first connecting
link, pin and one lug pair, and a second load bearing path along
the second connecting links, bushings, and the other lug pair;
projecting bosses may be provided on one lug pair of fuctionally
replace the flanged bushings in the second load bearing path. In
each embodiment including a bearing the second link members may be
pivotally connected with large tolerances to permit the first link
to pivot about an axis perpendicular to the axis of the pin to
impart a degree of self-alignability to the connector.
Inventors: |
Arnold; Alison M. (Greenbank,
WA), Reed; Ronald G. (Renton, WA) |
Assignee: |
The United States of America as
represented by the Secretary of the Air (Washington,
DC)
|
Family
ID: |
24815162 |
Appl.
No.: |
06/700,857 |
Filed: |
February 12, 1985 |
Current U.S.
Class: |
403/79; 403/11;
403/156 |
Current CPC
Class: |
F16C
11/045 (20130101); Y10T 403/32221 (20150115); Y10T
403/32909 (20150115); Y10T 403/16 (20150115) |
Current International
Class: |
F16C
11/04 (20060101); B25G 003/00 (); F16D
001/00 () |
Field of
Search: |
;403/157,158,11,70,71,79,376,13,156 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Brown; David H.
Attorney, Agent or Firm: Scearce; Bobby D. Singer; Donald
J.
Government Interests
RIGHTS OF THE GOVERNMENT
The invention described herein may be manufactured and used by or
for the Government of the United States for all governmental
purposes without the payment of any royalty.
Claims
We claim:
1. A dual loading bearing path connector for pivotally joining a
movable member to a structural member, comprising:
a pair of spaced apart lugs, each said lug including at a first end
thereof means for attachment to one of said movable member and said
structural member, each said lug further including at a second end
thereof means defining an eyelet and an outwardly projecting
boss;
a clevis disposed between said lugs and including means for
attachment to said first member, said clevis having an eyelet
defined in the end of each leg thereof disposed in registration
with a corresponding eyelet in said lugs;
a pivot pin received by the eyelets of said lugs and said
clevis;
a self-aligning bearing, supported on said pin between the legs of
said clevis;
a first connecting link pivotally supported at a first end on said
bearing, and disposed for operative connection at a second end to
the other of said movable member and said structural member, said
first connecting link, bearing, pin and clevis providing a first
load bearing path between said structural member and said movable
member; and
a pair of second connecting links, pivotally supported at
respective first ends on a corresponding said projecting boss of
said lugs, and disposed for operative connection at respective
second ends to the other of said movable member and said structural
member, said second connecting links, projecting bosses, and lugs
providing a second load bearing path between said structural member
and said movable member.
2. The connector as recited in claim 1 wherein each of said second
connecting links includes an oversize hole at the first end thereof
for receiving a said projecting boss thereby permitting said first
link to pivot on said self-aligning bearing about an axis
perpendicular to the axis of said pin whereby said connector may be
self-aligning.
3. The connector as recited in claim 1 further comprising means for
connecting said second connecting links to said first connecting
link for movement therewith.
4. A dual load bearing path connector for pivotally joining a
movable member to a structural member, comprising:
a pair of spaced apart lugs, each said lug including at a first end
thereof means for attachment to one of said movable member and said
structural member, each said lug further including at a second end
thereof means defining an eyelet and an upwardly projecting
boss;
a clevis disposed between said lugs and including means for
attachment to said first member, said clevis having an eyelet
defined in the end of each leg thereof disposed in registration
with a corresponding eyelets in said lugs;
a pivot pin received by the eyelets of said lugs and said
clevis;
a first connecting link pivotally supported at a first end on said
pin, and disposed for operative connection at a second end to the
other of said movable member and said structural member, said first
connecting link, pin and clevis providing a first load bearing path
between said structural member and said movable member; and
a pair of second connecting links, pivotally supported at
respective first ends on a corresponding said projecting boss of
said lugs, and disposed for operative connection at respective
second ends to the other of said movable member and said structural
member, said second connecting links, projecting bosses, and lugs
providing a second load bearing path between said structural member
and said movable member.
5. The connector as recited in claim 4 further comprising means for
connecting said second connecting links to said first connecting
link for movement therewith.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to multiple load path
connectors for fail-safe structural or load carrying mechanical
joints and more particularly to a novel pinned clevis or double lug
pair connection wherein two separate load bearing paths are
provided to carry a load in a fall-safe manner, one path carrying
the load upon failure of the other.
Prior attempts to provide multiple load path joint connectors have
included use of a pin-within-a-pin arrangement and dual clevis or
lugs. Also, large diameter pins have been used to provide a low
stress level and extended safe life design. These solutions may
ordinarily be suitable when sufficient space exists for their
installation. However the use of large diameter pins requires large
lug or clevis dimensions, and, if bolt clamp-up is desired for
preloads in reducing bolt bending stresses, large size bolt heads
and nuts are also required. For certain applications such as in the
mechanical linkages for movable airfoils on aircraft, unlimited
working space and weight allowance are not available. Multiple load
path connections may nevertheless be required for safe life
aircraft design for redundant structural or mechanical connections
in areas where a single failure may result in loss of the
aircraft.
The present invention provides a novel single pin structural or
mechanical joint including a primary and a standby load path across
the joint. The pivotal connector configuration disclosed herein may
be applicable to simple pin joints or to self-aligning joints
requiring rotational alignment about axes other than the pin axis.
The invention provides a mechanical joint which may include both
safe life and dual load path characteristics and which may be
inspected for component failure without disassembling the joint.
Further, the present invention avoids space availability problems
characteristic of existing structures wherein space for
self-aligning joints in a diametrical direction may be limited,
which may be characteristic of certain existing thin wing fighter
aircraft, by using slightly increased amount of space in an axial
direction which is often available.
It is, therefore, a principal object of the present invention to
provide an improved multiple load path connector.
It is a further object of the invention to provide a dual load
path, fail safe, single pin connector for structural or mechanical
joints.
It is a further object to Provide a self-aligning dual load path
pivotal connector for control linkage or support for movable
airfoils on aircraft.
These and other objects of the present invention will become
apparent as the detailed description of certain representative
embodiments thereof proceeds.
SUMMARY OF THE INVENTION
In accordance with the foregoing principles and objects of the
present invention, a novel dual load path connector for pivotal
joining a movable member to a structural member is described which
comprises a pair of spaced apart lugs attached to a first of the
members, each of the lugs including an outwardly projecting boss, a
clevis disposed between the lugs and attached to the first member,
a pivot pin, received by the lugs and clevis, which may support a
self-aligning bearing between the ends of the clevis, and a
connecting link assembly including a first connecting link
pivotally supported at a first end on the pin and connected at the
other end to the second member, and a pair of second connecting
links pivotally supported at respective first ends on the bosses
and at the second ends to the second member, the first connecting
link, pin and clevis providing a first load bearing path between
the structural and movable members, and the second connecting
links, bosses and lugs providing a second load bearing path.
Alternatively, a pair of spaced apart fail safe lugs attached to
the first member and a pair of flanged bushings received by the
lugs may be utilized to provide a first load bearing path along the
first connecting link pin and lugs and a second load bearing path
along the second connecting links, flanged bushings, and lugs. In a
further embodiment, two pairs of spaced apart lugs are attached to
the first member and a pair of flanged bushings are received by the
respective lug pairs to provide a first load bearing path along the
first connecting pin and one lug pair and a second load bearing
path along the second connecting links, bushings, and the other lug
pair; projecting bosses may be provided on one lug pair to
functionally replace the flanged bushings in the second load
bearing path. In each embodiment including a bearing the second
link members may be pivotally connected with large tolerances to
permit the first link to pivot about an axis perpendicular to the
axis of the pin to impart a degree of self-alignability to the
connector.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more clearly understood from the
following detailed description of certain representative
embodiments thereof read in conjunction with the accompanying
drawings wherein:
FIG. 1 is an axial sectional view of an embodiment of the present
invention comprising a dual load path pin and clevis joint.
FIG. 2 is an axial sectional view of an embodiment including a
pinned joint with bushings and safe life lugs.
FIG. 3 is an axial sectional view of an embodiment including double
lug pairs and bushings.
FIG. 4 is an axial sectional view of an embodiment including double
lug pairs, one pair including boss projections.
FIG. 5 is an axial sectional view of a non-self-aligning pinned
joint with bushings and safe life lugs.
FIG. 6 is an axial sectional view of a non-self-aligning pinned
joint including double lug pairs and bushings.
FIG. 7 is an axial sectional view of a non-self-aligning pinned
joint including double lug pairs, one pair including boss
projections.
DETAILED DESCRIPTION
Referring now to FIG. 1, shown therein is a sectional view of one
embodiment cf the present invention comprising a self-aligning
pinned joint including a clevis and lug pair to provide a dual load
path. Dual load path joint 10 may preferably comprise a connecting
member in the form of a clevis 11 and a pair of lugs 12,13 on
either side of clevis 11 for making connection between a load path
linkage assembly 14 and a load carrying or structural member 15.
Clevis 11 and lugs 12.13 may be joined to structural member 15
conventionally, as by bolts 16 or the like. Lugs 12,13 include boss
protrusions 12a, 13a machined thereon for carrying linkage assembly
14 in part as hereinbelow detailed.
The multiple load path linkage assembly 14 may comprise three
linkage member sets each, including a center member assembly 17
between two outer member assemblies 18a,18b, separated by spacers
19a,b, as suggested in FIG. 1. Linkage member sets 17,18a, 18b, and
19a,19b may be connected seriatim by bolts, pivot pins or the like
as represented schematically the broken centerline 20. The function
of the linkage member assembly 14 is to feed the load from or into
joint 10 for transfer from or to structural member 15 through
clevis 11 and alternatively through lugs 12,13. The connecting end
of center member assembly 17 of linkage assembly 14 includes a
self-aligning hearing 21 received between the ends of clevis 11 and
supported on transversely disposed threaded pin 22 along assembly
axis A through the eyelets of clevis 11. The connecting ends of
outer member assemblies 18a,18b of linkage assembly 14 are received
on boss protrusions 12a,13a, substantially as shown in FIG. 1. A
nut 23 on threaded pin 22 secures the assembly together as
shown.
The center linkage member 17 carried out on self-aligning bearing
21 comprises the normal load carrying member in the linkage
assembly; the outer members 18a,18b, which may preferably include
oversize holes for receiving boss protrusions 12a,13a, comprise the
alternate or standby load bearing members The normal or primary
load bearing path is therefore along center member 17,
self-aligning bearing 21. Pin 22, and clevis 11 to load carrying
structural member 15. The standby load path along outer member
assemblies 18a,18b, bosses 12a,13a and lugs 12,13 assumes the load
upon failure of an element along the primary load path. The pivotal
connections between members 18a,18b with bosses 12a,13a may be
characterized by large assembly clearances to permit some rotation
of center member 17 on self-aligning bearing 21 about an axis
perpendicular to axis A, in order for joint 10 to be self-aligning
with respect to the direction of load application.
FIG. 2 illustrates an axial sectional view of a pinned joint 25
including bushings and safe life lugs. In joint 25, the primary
load path is along center linkage member assembly 27 pivotally
supported on pin 28 through a self-aligning bearing 29 in fashion
similar to the joint 10 configuration of the FIG. 1 embodiment. The
secondary load path linkage member assemblies 30a,30b are pivotally
connected to safe life lugs 31a,31b through a pair of flanged
bushings 32a,32b received by the eyelets of lugs 31a,31b and
enclosing self-aligning bearing 29 therebetween. As with joint 10
of FIG. 1, the assembly clearances of linkage members 30a,30b may
be large to allow some pivoting of linkage member 27 on
self-aligning bearing 29, thereby allowing the entire joint 25 to
be self-aligning.
FIG. 3 presents an alternative configuration similar to that shown
in FIG. 2 and including dual lug pairs of redundancy rather than
safe life lugs. Accordingly, joint 34 of FIG. 3 includes outer lugs
35,36 and an inner lug 37 carrying a pair of flanged bushings 38a,b
on threaded pin 39. Self-aligning bearing 41 is pivotally supported
on pin 39 and carries one end of center link member assembly 42.
The connecting ends of outer link member assemblies 43a,43b are
pivotally connected on the flanges of bushings 38a,b. Therefore,
center link member assembly 42, self-aligning bearing 41 and inner
lug 37 may comprise one (primary) load path to a structural load
carrying member (not shown), and outer link member assemblies
43a,b, bushings 38a,b and outer lugs 35,36 may comprise the
alternate or standby load path.
FIG. 4 presents a joint 44 similar to that of FIG. 1, but includes
dual load path lug pairs comprising outer lugs 45,46 and inner lugs
47,48 and buss projections 47a,48a on the inner lug pair.
Accordingly, in joint 44 of the FIG. 4 embodiment, the primary load
path is along center link member assembly 52, self-aligning bearing
51, pin 49 and outer lugs 45,46 to the structural load bearing
member (not shown). The standby load path is along outer link
member assemblies 53a,53b, bosses 47a,48a and inner lugs 47,48.
Bosses 47a,48a included on the inner surfaces of lugs 47,48
immediately adjacent self-aligning bearing 47 provide somewhat
greater tolerance limits at the outer lugs 45,46 along the
secondary or standby load path, which may give center linkage
assembly 52 somewhat more rotational freedom on self-aligning
bearing 51, and consequently somewhat greater degree of
self-alignability to joint 44, than that which characterized the
other described embodiments.
FIG. 5 illustrates an axial sectional view of a non-self-aligning,
dual load path pinned joint 55 including bushings and safe life
lugs. In joint 55, the primary load path is along center linkage
member assembly 58 pivotally supported on pin 59 to safe life lugs
57a,57b. The secondary load path is along outer linkage member
assemblies 60a,60b which pivotally connected to lugs 57a,57b
through a pair of flanged bushings 56a,56b received by the eyelets
of lugs 57a,57b.
FIG. 6 presents alternative non-self-aligning configuration
including dual lug pairs for load path redundancy rather than safe
life lugs. Accordingly, joint 61 of FIG. 6 includes outer lugs
62a,62b and inner lugs 63a,63b carried on a pair of flanged
bushings 64a,64b and threaded pin 65. Pin 65 carries one end of
center link member assembly 66. The connecting ends of outer link
member assemblies 67a,67b are pivotally connected on the flanges of
bushings 64a,64b. Therefore, center link member assembly 66, pin 65
and inner lugs 63a,63b may comprise the primary load path to a
structural load carrying member (not shown), and outer link member
assemblies 67a,67b, bushings 64a,64b and outer lugs 62a,62b may
comprise the standby load path.
FIG. 7 presents a non-self-aligning joint 71 including dual load
path lug pairs comprising outer lugs 72a,72b and inner lugs 73a,73b
and boss projections 74a,74b on the inner lug pair. Accordingly, in
joint 71, the primary load path is along center link member
assembly 76, pin 75 and outer lugs 72a,72b to the structural load
bearing member (not shown). The standby load path is along outer
link member assemblies 77a,77b, bosses 74a,74b and inner lugs
73a,73b.
In each of the described embodiments, a secondary of standby load
path through the joint provides means to carry a load through the
joint in the event of failure of an element along the primary load
carrying path. It is instructive to note that the secondary load
paths of the joints in each of the described embodiments will carry
the load in the event of failure of the pin, and even if the pin is
removed.
The present invention therefore provides a novel dual load path and
self-aligning pinned connector for pivotally movable, load carrying
joints. It is understood that certain modifications to the
invention as described may be made, as might occur to one with
skill in the field of this invention, within the scope of the
appended claims. Therefore, all embodiments contemplated hereunder
which achieve the objects of the present invention have not been
shown in complete detail. Other embodiments may be developed
without departing from the spirit of the invention or from the
scope of the appended claims.
* * * * *